Method of treating body insect infestation

ABSTRACT

Described is a safe and effective method for treating lice and nits (fleas, ticks and other insects) with a low surface tension lubricant.

FIELD OF THE INVENTION

[0001] This invention relates to the safe and effective treatment oflice, nits (and other infestational insects) by using low surfacetension lubricants.

BACKGROUND OF THE INVENTION

[0002] For centuries, people have been plagued by head lice, body lice,and pubic lice, which appear in numerous species all having similarphysiological characteristics. Over the years, people have expendedtremendous efforts and resources to develop a safe and effective methodfor eliminating the problem of lice and nits. To date, the only patentedprocesses for killing lice and nits involve the use of poisons,pesticides or noxious soaps with numerous side effects and cautionaryuses. These pediculicides, such as lindane, pyrethrun, or malathion, arenot optimal for the treatment of lice or nits because they are nothealthful, and because, over time, lice tend to develop a naturalresistance to poison or pesticide formulation.

SUMMARY OF THE INVENTION

[0003] It is accordingly an object of the present invention to provide amethod and chemical formulation for effective yet safe treatment forbody insect infestation such as lice, fleas, and the like.

[0004] Generally present the invention compromises the direct treatmentof body insect infestation with a synthetic lubricant, such as foodgrade silicon, to effectively kill infesting insects such as lice, andnits, as well as fleas, ticks and other insects. In Accordance with thepresent invention, the synthetic lubricant is applied directly to theinsects, or is provided as a major (more than 50 volume percent) of ashampoo formulation. If added to a shampoo, the exact effectiveconcentration level above 50% is determined based on both the nature ofthe synthetic lubricant, and the nature of the shampoo used.

DETAILED DESCRIPTION OF THE INVENTION

[0005] In order to illustrate the efficacy of the present invention thefollowing test examples are presented.

EXAMPLE 1

[0006] Two tests were conducted using a compound containing 60%silicone-based oil. In the first test the compound was placed on a louseon a paper towel. After 5 minutes, the louse washed off with Prell®shampoo and water. The louse was observed one minute later and was dead.In the second test using the same compound, the compound was applied tothe long, thick hair of a school girl, which had been infested with licefor several months. After five minutes, the compound was removed byseveral washes with Prell® shampoo, with the compound being otherwisedifficult to extract from the hair. The infestation was successfullytreated and no lice or nits returned.

EXAMPLE 2

[0007] Additional tests were conducted using a 100% concentration of Dowcorning Fluid Food Grade silicone (350 CST) (the “silicone”). Thesetests also revealed that, in addition to killing lice, the silicone waseffective at preventing nits from maturing. In these tests, silicone wasapplied directly to head lice, body lice, and to the hair of severalchildren infested with head lice.

[0008] In the first Silicone experiment three head lice were collectedfrom school children. The lice were placed on the hand of a subject andthey attached themselves to the hair on the subject's hand. After fiveminutes, the lice were gently washed off with Prell® shampoo and thenwater.

[0009] Although there appeared to be mortality within minutes, the licewere left on the hand for further examination (they were covered with aloosely fitting bandage to make sure they did not fall off). During thefollowing six hours, the lice were checked periodically and all werefound to be dead.

EXAMPLE 3

[0010] In a further Silicone experiment, Silicone was directly appliedto the hair of three school children, each of which had been infestedwith lice and nits. Each of the children applied the silicone directlyto his or her hair and left it on for five minutes. After five minutes,the hair was washed first with Prell® shampoo and then with Johnson'sBaby Shampoo®. In all three cases the infestation was successfully endedwith one application.

[0011] In a continuing experiment, Silicone was directly applied to thehair of twenty school children, each of which had been infested withlice and nits. Each of the children applied the silicone directly to hisor her hair and left it on for ten minutes minutes. After ten minutes,the hair was washed with a shampoo of the parent's choice. In all twentycases the infestation was successfully ended with one application.

EXAMPLE 4

[0012] In another experiment ten adult lice were immersed in theSilicone for ten minutes, then washed and rinsed for one minute each inwater. A set of ten control lice were immersed in water for ten minutesand then also washed and rinsed for one minute. The lice were then heldin an incubator. A review of the lice after one hour, and again aftertwenty-four hours, revealed a 100% morality of those who had beenimmersed in Silicone. There was no morality among the controls.

EXAMPLE 5

[0013] In an additional experiment, ten adult lice were immersed in theSilicone for ten minutes, and subsequently washed in a dilution of 50:50Johnson's Baby Shampoo® and tap water. To test the effectiveness atdifferent concentrations of Silicone, four mixtures were made using theSilicone with Johnson's Baby Shampoo® with the following concentrations:

[0014] a. 100% Johnson's Baby Shampoo

[0015] b. 3% Silicone and 97% Johnson's Baby Shampoo

[0016] c. 15% Silicone and 85% Johnson's Baby Shampoo

[0017] d. 40% Silicone and 60% Johnson's Baby Shampoo

[0018] e. Control with water

[0019] The results of the test after 24 hours were that for samples aand c, one louse was dead; for samples b and e, no lice were dead. Theone louse being dead was considered not statistically significant. Insample d, containing 40% Silicone, four lice were dead, indicating thatat this concentration there is some effectiveness of the Silicone inkilling lice but not a fully useful concentration. It is believed thatother ingredients may interfere with the effectiveness of the Silicone,and accordingly it is preferred to use the Silicone in a highconcentration or in a pure state.

EXAMPLE 6

[0020] In another experiment to determine the effect of lubricants ofvarious surface tensions, a test was done using 10 adult lice immersingthem into one of three solutions for ten minutes and then washing themof with a soapy water solution. The three lubricants used were Johnson'sbaby oil a mineral oil, Ultra pure lamp oil 99% pure liquid paraffin,and Krytox® 1514 Vacuum pump fluid, produced by Dupont®. The lice werethen observed after one hour, and three hours and the amount dead werethe same at both intervals in all tests. The mortality rate was highestfor the Krytox® 1514 with nine of ten dead within one hour, lowest forthe liquid paraffin with three of ten dead within one hour, and moderatefor the mineral oil with four of ten dead within one hour. In a repeatof the experiment for the Krytox, seven out of ten where dead within onehour, for liquid paraffin two out of ten, and for mineral oil five outof ten.

[0021] The preferred embodiment for use as a head lice treatment is touse the Silicone in its pure state, that is Dow Coming 200 fluid, 350CST. Which is a silicone fluid termed Dimethyl polysiloxane. TheSilicone is water white and has a consistency of light syrup. This formis preferred as it clings easily to the hair. The Silicone is applied tothe entire head, left on for at least ten minutes, and then washed offwith any standard shampoo. Within a short time after application of theshampoo, the area is free of any live lice. Any nits do not mature.

[0022] Other embodiments include the processing of synthetic lubricantsinto a shampoo that effectively kills ticks, fleas, and other insects.The concentration of such lubricants, and the amount of time they mustremain on the affected area, is above 50% by volume and is adjusteddepending on the type of insect being treated. Thus, for example, in twoexperiments conducted on ticks, the ticks took longer to die than thelice did in the prior experiments using pure Silicone treatment. In thefirst tick experiment, ten Amblyomma Americanum ticks were coated withSilicone, and ten were coated with Prell® Shampoo. After ten minutes,both sets of ticks were washed with water and Prell® Shampoo for fiveminutes, until all of the Silicone and shampoo were removed. While allof the “Silicone” ticks were alive after one hour, after six hours threeof the ticks were dead, five were morbid, and two were alive. Aftertwenty-four hours, all of the “Silicone” ticks were dead, whereas onlytwo of the “Prell®” ticks were dead.

[0023] In a second tick experiment, ten Dermacentor Varibilis ticks werecoated with Silicone. After ten minutes all of the ticks were stillalive. After ninety minutes, all of the ticks were dead.

[0024] While Silicone has been used for many years as a hair-bodyingagent, and there are many patents (U.S. Pat. No. 3,964,500, U.S. Pat.No. 4,427,557, U.S. Pat. No. 4,465,619, U.S. Pat. No. 4,704,272, U.S.Pat. No. 5,728,457, U.S. Pat. No. 4,749,732, U.S. Pat. No. 4,842,850,U.S. Pat. No. 5,015,415, U.S. Pat. No. 5,034,218, U.S. Pat. No.5,063,044, U.S. Pat. No. 4,902,499, U.S. Pat. No. 4,906,459, U.S. Pat.No. 5,554,313, U.S. Pat. No. 577,644) that focus on using silicone, andsome specifically polysiloxanes, for various benefits to the hair. Suchuse levels have always been at concentrations below 50% whereineffectiveness for insect control was not evident. For actualeffectiveness use in the range of 50-100% concentration is required.

[0025] It is believed that the lubricating properties of the siliconeprovide a morbidity passageway for interfering with insect respiratoryand possibly digestive functions, and accordingly other similarlubricants and Silicone derivatives are effective in such insectcontrol.

[0026] With regard to head lice, the point of entry where the siliconepermeates the head lice is very likely the thoracic spiracle, thehoneycomb structure which creates maximum surface area and efficientexchange of air and moisture. The nits are likely affected via the headlouse nit operculum which contain doughnut shaped holes. See Meinking,T. L. Current Problems in Dermatology 11 (3) pp 73-120 May/June 1999.

[0027] With regard to head lice many natural oils treatments have beenattempted but with limited efficacy. In a school based study to evaluatealternative treatments, children with head lice were treated with oliveoil, mayonnaise, or Vasoline® petroleum jelly overnight under a showercap. They came to school the next day with their greasy hair stillcovered by shower caps. After a shampoo rinse, the lice from headstreated with olive oil or mayonnaise were found to still be alive. Thechildren who used Vasoline® had many dead nymphs stuck to the scalp orhair but some adult lice were still alive. See Meinking, T. L., ibid.

[0028] The efficacy of silicone based lubricants over other oils appearsto be related to the lubricity of silicone. Silicone and moreparticularly Dimethylpolysiloxane (or Polydimethylsiloxane) has a farlower surface tension than other oils. Surface tension is a measure ofthe stretching force required to form a liquid film, and is equal to thesurface energy of the liquid per unit length of the film at equilibrium:the force tends to minimize the area of a surface. Surface tension iscaused by the attraction of molecules to each other.

[0029] Below is a list of the surface tension of a variety of polymersand oils at 20° C. Polymer/oil system Surface Tension (dynes/cm)Polydimethylsiloxane (PDMS) 20.9¹ Polyisobutylene (PIB) 35.6¹ n-alkanes37.8¹ n-fluoroalkanes 25.9¹ diesel fuel 25² deodorized sunflower oil 33²crude soybean oil 32² refined soybean oil 32² cottonseed oil 35.4³coconut oil 33.4³ olive oil 33.0³ corn oil 33.4⁴ peanut oil 35.5⁴mineral oil (MWP paraffin) 28.8⁴ mineral oil-baby oil 30.8⁵ liquidparaffin 26-28⁵ Krytox 1514 18⁶

[0030] The surface tension of polydimethylsiloxane at about 20.9dynes/cm is about 50% lower than the surface tension of most naturaloils and is believed to account for its greater ability to penetrate andinduce morbidity in insects. In our experiment with Krytox® 1514 afluorinated oil PerFluoroPolyEther (PFPE), with a surface tension of 18,we found that it was also effective in killing lice but slightly lesseffective than Dow Coming 200 fluid, 350 CST . The greater effectivenessof the Dow Corning 350 CST material is very likely due to the itsgreater viscosity. Viscosity , or kinematic viscosity is measured instokes, and is defined to be the dynamic viscosity divided by thedensity of the liquid; this gives a quantity which depends only on thetype of the liquid. independent of its concentration or density.Krytox1514 has a viscosity of 142 centistokes (cst), while Dow Corning200 fluid, 350 CST has a viscosity of 350 cst. The viscosity adds to theeffectiveness by creating better adhesion of the lubricant to theinsects.

[0031] Attempts have been made to modify vegetable oils thru processessuch as transesterification in order to lower their surface tensions andthus make them usable as biodiesel fuels. See Cecil, A. W.; Allen, K.;Watts. C. and Ackman R. G. in “Predicting the Surface Tension ofBiodiesel Fuels from Their Fatty Acid Composition”, JAOCS 76(3), pp.317-323 (March ,1999). It is probable that if vegetable or other oilswere processed to lower their surface tension close to the surfacetension found in polydimethylsiloxane i.e. less than about 25dynes/centimeter, it would have the same effect on the lice.

What is claimed is:
 1. A method of treatment of body insect infestationcomprising the step of topically applying a lubricant with a surfacetension below about 25 dynes/centimeter (at 20° C.) to the body insectinfestation and allowing the lubricant to remain on the insectinfestation for a time sufficient to allow for complete killing of allinsects.
 2. A method of treatment of body insect infestation where thelubricant claimed in claim 1, has a viscosity above about 200centistokes (at 20° C.).
 3. A method of treatment of body insectinfestation as claimed in claim 1 where the lubricant comprisesdimethylpolysiloxane.
 4. A method of treatment as claimed in claim 1where the infestation is any form of pediculosis including head, body orpubic lice.
 5. A method of treatment as claimed in claim 1 where theinfestation are lice, ticks and fleas in animals.